The effect of irrigation practices on stress-related physiological characteristics, water productivity, and water footprint in rice cultivation

Water plays a critical role in rice cultivation, a major export commodity in Thailand, especially under climate-induced drought conditions. This study evaluated the impact of three irrigation practices—continuous flooding (CF), alternate wetting and drying (AWD), and saturated soil irrigation (SSI)—on physiological parameters and water usage in paddy fields. The results showed no significant differences in physiological traits such as stomatal conductance (g_sw), leaf temperature (T_leaf), chlorophyll fluorescence (F_s), quantum yield (Φ_PsII), osmolality, and MDA content. However, water consumption differed notably: in the first crop season, CF, SSI, and AWD used 9,931, 7,106, and 7338 m³/ha, respectively, while in the second season, usage was 9,427, 5,746, and 5794 m³/ha. Grain yield remained similar across treatments: 4.13, 4.03, and 4.08 tons/ha in the first crop season, and 4.21, 4.23, and 4.66 tons/ha in the second crop season for CF, SSI, and AWD, respectively. Water productivity (WP_IR) for CF, SSI, and AWD was 0.42, 0.57, and 0.56 kg m⁻³ in the first crop season and 0.45, 0.74, and 0.80 kg m⁻³ in the second crop season. The consumptive water footprint (WF_consumption) also varied, with values of 2,607, 1,976, and 2007 m³/ton in the first crop season and 2,431, 1,549, and 1401 m³/ton in the second crop season, with the highest in the direct blue water footprint category. AWD and SSI significantly increased water productivity. The study underscores the potential of physiological data as a tool to inform sustainable on-farm irrigation strategies. The integration of such practices could contribute to climate-resilient and resource-efficient rice production systems.